Fabrication of well-aligned and dumbbell-shaped hexagonal ZnO nanorod arrays and their dye sensitized solar cell applications

Dumbbell-shaped hexagonal and well-aligned ZnO nanorod arrays (NRAs) were fabricated by simple and low temperature aqueous solution technique on ZnO-coated FTO substrate and in solution respectively. Structural analysis revealed an excellent crystal quality and wurtzite hexagonal structure of ZnO nanostructures. ZnO nanostructures were used as the wide band gap semiconducting photoelectrode in dye-sensitized solar cells (DSSCs). Well-aligned ZnO NRAs were greatly enhances dye adsorption, leading to improved light harvesting and overall efficiencies. Solar cells made from aligned ZnO NRAs showed photocurrents of 2.08 mA/cm2, internal quantum efficiencies of 34.5%, and overall efficiencies of 0.32%. However, DSSC made from the randomly formed dumbbell-shaped hexagonal ZnO nanorods showed efficiency about 0.26%, with internal quantum efficiency of 31.5% respectively.